Maintenance of human sperm motility and prevention of oxidative damage through co-culture incubation

Co-culture incubation is one of the important techniques used in basic and clinical research of assisted reproduction. In this study, sperm samples from 40 healthy donors were prepared for co-culture incubation with Vero cells which had been derived from the kidney fibroblasts of the African green monkey, Cercopithecus aethiops. We found that the motility characteristics of ejaculated human sperm co-cultured with Vero cells were largely maintained and the percentage of hyperactivated sperm in the co-culture group was not affected. While the sperm of the control group completely lost the motility at 12 h incubation at 37°C in 5% CO₂, the sperm co-cultured with Vero cells still maintained 74% of the original motility. Lipid peroxidation and accumulation of 8-hydroxy-2'-deoxyguanosine spermatozoa were also reduced by the co-culture incubation, which strongly indicates that intercellular interactions may play some role in the maintenance of sperm functions. We conclude that the oxidative damage in vitro of the sperm can be reduced by the co-culture system and thereby maintains the function of sperm from oxidative damage.